High frequency antennas



Feb. 5, 1957 M. P. MIDDLEMARK 9 9 I HIGH FREQUENCY ANTENNAS w 7 Filed Dec. 15, 1953 45 42 ATTORNEY 2,780,808 Fatentecl Feb. 5, 1957 HIGH FREQUENCY ANTENNAS Marvin P. Middlemark, Woodside, N. Y. Application December 15, 1953, Serial No. 398,291

3 Claims. (Cl. 343--806) This invention relates to high frequency antennas for principal use with television or other high frequency apparatus and is a continuation in part of my prior application Serial No. 241,959, filed August 15, 1951, now Patent No. 2,749,543.

In the above mentioned application, I described an antenna system comprising an antenna array in combination with a selector switch which combined various dipole elements of the array to provide selective directivity. The instant application, in one form thereof, discloses an antenna system which is used in the same general arrangement but it also discloses specific forms of antenna elements which have considerable utility apart from any specific forms of antenna systems.

In accordance with the instant invention there is provided antenna elements or dipoles which are of novel form and which produce extremely high gains. The basic antenna element or dipole may be used in a simple antenna structure or it may be used in a multi-directional system as above described. The basic element or unit, whether alone or in the complex array, provides particularly good results at all regions of the television spectrum as now employed.

I have achieved the results above mentioned by forming each dipole section into a multi-folded or sinuous structure, the folds being uniformly separated by integral spacer elements, two dipole sections comprising one dipole. Each dipole section or unit is itself symmetrical and connections are ordinarily made to a center point thereof.

The basic antenna element or unit of the instant invention particularly lends itself to stacking arrangements as will appear hereinafter.

The invention will be further understood from the following description and drawings in which:

Figure 1 is a perspective view of an antenna system constructed according to the instant invention;

Figure 2 is a side elevational view of a single unit or element thereof;

Figure 3 is a side elevational view of a more complex form of single element wherein effective stacking is achieved;

Figure 4 is a perspective view of a substantially bidirectional antenna array formed from two of the basic elements of the invention;

Figure 5 is a perspective view of a fixed directional type of antenna formed from four of the basic elements of the invention;

Figure 6 is an elevational view of an antenna employing two of the basic elements as aligned dipole elements; and

Figure 7 is an elevational view of an antenna similar to Figure 6 but where the adjacent ends of the units are interconnected.

Referring to Figure 1, the array illustrated comprises four basic units or antenna elements 10 spaced 90 apart. Each element comprises two folded portions 11 and 12 which are integrally connected by a bar or link 13 at the inside line of the element. Bar 13 is of the same length as the outside fold bars or links 14 and 15. All of the sections 11 to 15 are integral, being formed of one length of metal folded or bent in a sinuous structure as shown. As is conventional in the general form of antenna arrays illustrated, an insulating bracket, notv shown. is generally employed to physically support the antenna elements, usually by suitable connection to the: connecting bars 13.

In accordance with the all-directional system, details of which will be further supplied hereinafter, four wires 16 are respectively connected to the four connecting bars 13. Such wires are introduced into a selector switclr 17, the construction of which may follow the form shown in my above mentioned application Serial No. 241,959, or my issued Patent No. 2,585,670 wherein the sameswitch is shown.

Switch 17 includes a selector knob which serves to apply any two antenna elements 10 to a pair of output wires 19 and 20. The output wires are connected to input terminals of a television receiver. Accordingly, and as set forth in my prior patents, any two antenna elements may be selected for connection to a television receiver so as to effectively vary the directivity of the system in accordance with requirements.

The basic antenna element 10 is shown in elevation in Figure 2. Inasmuch as such an element functions as a dipole rod, two of which may be considered as making up a dipole, the element may be considered as a dipole section or half a dipole. It has been found that optimum results are attained by making the vertically spaced, parallel horizontal lengths, i. e., lengths 2124, about four times as long as the connecting links or folds 13-15 which are disposed substantially perpendicular to the horizontal lengths. In one embodiment designed for the television band occupying the very high frequency region, the horizontal lengths 2124 were 48" and the connecting lengths 13-15 were accordingly 12". It will be understood that some deviation from these proportions is permissible without sacrificing the advantages of the invention. Thus, making the lengths 21-24 little more than three times the length of the folds also produced satisfactory results. Satisfactory results have also been produced with length ratios substantially greater than the required embodiment, the ratio illustrated being the optimum for most purposes. It will further be noted that both the topmost length 21 and the lowermost length 24 terminate at their open ends and both extend to such termination in the same direction.

The basic unit shown in Figure 2 has been found to provide unusually high gains. When used in the ultrahigh frequency region, the unit may be made smaller but the ratio of the length of the horizontal elements to the vertical elements will be substantially the same. However, the same basic unit may serve both bands.

The basic unit disclosed in Figure 2 lends itself to unusually facilitated stacking arrangements as illustrated in Figure 3. The stacking may be vertical as shown, orhorizontally as conventional, alternate units being inter connected. In vertical stacking, the two parallel lengths;

25 and 26 connected by a connecting link or fold 27, are very easily stacked to the two lengths 28 and 29 by means of an additional connecting link or fold 30. Thus eight horizontal lengths and seven connecting links are provided, the links interconnecting adjacent ends of said lengths at alternately opposite sides of the composite element. The wire connections are made to the link 30. Actually, the pattern could be indefinitely extended upwards and downwards within practical physical limits. Extremely high gains can be realized by employing a stacking arrangement in the manner described and the construction of such a stacked array is of utmost simplicity.

IiirFigure 4 is-illustrated"a-p=air of basic, complementary units .which. are conventionally insulated from each. other.

and inclined toward each other so as to define an angle of anywhere from 50 to 150 between them. It will be understood by those skilleddntlie art that a forwa'rd inclination of antenna elements is conventional in the art except that known dipole elements were employed;

Figure'A-thus illustrates the use of my basic units in such ment, units-31 and'34 are interconnectedby-a shorting' wire *orbar 35 while'a'similar-bar or-wire 36'shorts the elements 32 and 33, such shorting beingat the inside connecting links. Wires 37 and 38 are applied directly to: the input terminals of the television receiver. The antenna array of Figure operates bi-directionally as illustrated by thearrow 39.

In Figure 6 is illustrated the use of two-of the basic unitsaligned in a vertical plane so as to take thefo'rm of'a conventional straight dipole. Such an antenna may be used alone or in any environment where a straight dipole is conventionally used.

Figure 7 is-similar to the arrangement shown-in Figure 6 save that thetop and bottom horizontallengths 40 to 43 are respectivelyinterconnected, i. e., horizontal length 40 being connected to length 41 while length 421is-connected to length 43. This arrangement is permissible because the inner ends of the horizontal-lengths are at the same voltage level and no electrical change is made by interconnecting themr This lends itself to more convenient construction practices in that a metallic mast 44 may have the ends of the horizontal lengthsv directly connected thereto as illustrated in Figure 7. This produces a sturdy'structure and may eliminate the neces sity'for a central supporting bracket. The wires 45 and 46=are applied to the input terminals of a television receiver.

What is claimed is:

of metal, three links interconnecting said lengths-to ad jacent' lengths'to form a continuous, sinuous structure, said links being substantially perpendicular to said lengths,

two of said links being at one-side of said element and spaced: from each other and the remaining link beingat-theopposite side of said element and disposedcen trally of said opposite side, said remaining links of each element being adjacent eachother, and connecting-wires extending from each of said two remaining links and adapted to be connected to the input terminals of a television receiver.

2. A high frequency antenna comprising four antenna elements, said elements being disposed apart and effectively radiating from a substantially common center, each element comprising at least four parallel lengths of metal, three links interconnecting said lengths to adjacent lengths to form a continuous, sinuous structure, said links being substantially perpendicular to said lengths, two of said links being at one side of said elementand spaced from each other and the. remaining link being at the opposite side of said element and disposed centrally of said opposite side, the said remaining links of two adjacent elements being electrically connected to each other at their centers, and the other 'two remaining links being electrically connected to each other,'- said lengths and said links having a length ratio of approximately four to one.

3. A high frequency antenna comprising at leasttwo mutually insulated and complementary elements, each of said elements comprising at least four parallel lengths of metal, three links interconnecting said lengths to'adjacent lengths to form a continuous, sinuous structure,

posed centrally of said opposite side, said" remaining links of each element being=adjacenteach other, and connecting wiresextending from the center of each of said two remaining links andadapted'to be connected to the input terminals of a television receiver," both the topmost and the lowermost of said" parallel lengths extendingto a terminating open end thereofin the same"- direction.

References Cited in the file of this'patent' UNITED STATES PATENTS 1,987,780 Latour Jan. 15, 1935 2,039,988 Graves May 5, 1936' 2,066,900 Posthumus et al. Jan. 5, 1937 2,283,914 Carter May 26-, 1942' 2,472,106 Hansen June -7, 1949' 2,480,153 Masters Aug. 30, 1949 2,507,225 Scheldorf May 9, 1950 FOREIGN PATENTS.

864,707 Germany' Jam: 26, 1953 

